Implantace do prïipraveneâ mezery prïi agenezi hornõâho postrannõâho rïezaâku Dental implant into the prepared space in upper lateral incisor agenesis

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Implantace do prÏipravene mezery prÏi agenezi hornõÂho

postrannõÂho rÏezaÂku

Dental implant into the prepared space in upper lateral

incisor agenesis

*MUDr. Alena MottlovaÂ, **MUDr. Martin Kotas, Ph.D., *doc. MUDr. AntonõÂn SÏimuÊnek, CSc.

*Stomatologicka klinika LeÂkarÏske fakulty UK a FN v HradciKraÂloveÂ

*Clinic of Stomatology, Medical Faculty of Charles University and University Hospital, Hradec KraÂlove **Klinika zubnõÂho leÂkarÏstvõ LeÂkarÏske fakulty UP a FN v Olomouci

**Clinic of Dental Medicine, Medical Faculty of Palacky University and University Hospital,Olomouc

Souhrn

CõÂlem teÂto praÂce bylo zjistit charakteristiku mezer ortodonticky prÏipravovanyÂch k zavedenõÂ implantaÂtu na mõÂsto postrannõÂho hornõÂho rÏezaÂku z hlediska jejich vyuzÏitelnosti pro zavedenõÂ implantaÂtu a vztahu implantaÂtu k soused-nõÂm zubuÊm. Pozornost byla zameÏrÏena na bezpecÏnou/nebezpecÏnou zoÂnu implantace z meziodistaÂlnõÂho aspektu. DõÂlcÏõÂm uÂkolem bylo zjistit mõÂru zveÏtsÏenõÂ diagnostickeÂho ortopantomogramu, a zda toto zveÏtsÏenõÂ mohlo ovlivnit uÂsudek implantologa prÏi plaÂnovaÂnõÂ implantace.

VyÂzkumnyÂm materiaÂlem byly panoramaticke rentgenove snõÂmky 55 pacientuÊ s agenezõ alesponÏ jednoho hor-nõÂho postranhor-nõÂho rÏezaÂku, u kteryÂch byly na mõÂsta chybeÏjõÂcõÂch postrannõÂch rÏezaÂkuÊ zavedeny zubnõ implantaÂty a prÏed implantacõ jim byla mezera ortodonticky prÏipravena. Ortopantomogramy jsme hodnotili ve dvou cÏasovyÂch perio-daÂch: v cÏase T1 prÏed implantacõ a v cÏase T2 alesponÏ 6 meÏsõÂcuÊ po implantaci. Byla meÏrÏena vzdaÂlenost strÏednõÂho rÏezaÂku od sÏpicÏaÂku a pak vzdaÂlenost teÏchto zubuÊ od implantaÂtu a bylo sledovaÂno prÏõÂpadne narusÏenõ nebezpecÏne zoÂny implantace(Ortodoncie 2012, 21, cÏ. 3, s. 128-140).

Abstract

The aim of the study is to give characteristics of spaces that are orthodontically prepared for implant at the site of missing upper lateral incisor from the viewpoint of their suitability for the implant. The relationship of an implant to adjacent teeth was studied as well. We focus on comfort/danger zones from the mesiodistal aspect. We also want to identify the extent of magnification of the diagnostic panoramic radiographs (OPG), and to establish whe-ther the magnification can influence a surgeon's judgment in the planning of the implant placement.

We worked with OPGs of 55 patients with agenesis of at least one upper lateral incisor, in which the spaces were used for insertion of implants. The space was orthodontically prepared before the implantation. OPGs were evaluated in two time periods: T1 - before the implantation, T2 at least 6 months after the implantation. We mea-sured the distance between central incisor and canine, and then the distance of these teeth and the implant. We monitored eventual disruption of danger zone of the implant placement(Ortodoncie 2012, 21, No. 3, p. 128-140).

KlõÂcÏova slova:ageneze hornõÂch lateraÂlnõÂch rÏezaÂkuÊ, implantaÂt, bezpecÏne a nebezpecÏne zoÂny implantace Key-words:agenesis of upper lateral incisors, implant, comfort and danger zones for proper implant position

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Introduction

An implant is considered to be a crown prolonga-tion, and it should be placed with respect to the esthe-tic result of the prostheesthe-tic treatment. This approach is known as ¹restoration-drivenª and it is in contrast with the previous approach when the implantation was dri-ven solely by the potential of bone [1]. If there is lack of bone or soft tissues in the place of the planned implant placement, the deficiency must be restored with gui-ded tissue regeneration. The correct 3D placement of an implant depends on four parameters [2, 3]. An im-plant must be placed correctly in 3 dimensions - me-siodistal, orofacial and apicocoronal, and then it must be precisely angulated. In all three dimensions we di-stinguish the so-called comfort and danger zones of implantation. The implant location in comfort zone is the precondition of the favourable resulting esthetics of the process.

In mesiodistal dimension the danger zones are con-sidered with regard to adjacent teeth. Recently the width of danger zones was reviewed. Earlier works re-commended to insert an implant at least 1 mm from the surface of the root of the adjacent tooth. However, cur-rent research suggests that around the implant there naturally occurs funnel-shaped bone resorption not nearer than 1.5 mm. Therefore, the danger zone in me-siodistal dimension was reviewed at 1.5 mm from the adjacent tooth to the implant [2, 3, 4] (Fig. 1). The width of the space and the size of an implant must be plan-ned with regard to danger zones.

Facial margin of an implant should be placed 1 mm orally from the line connecting maximum convexities of neighbouring teeth. 2 mm orally off this imaginary line there is the danger zone of implantation. More pa-latal insertion of an implant results in disruption of gin-giva arch and the esthetic transition of the implant neck into the neck of supraconstruction. More vestibular placement of an implant results in alveolar bone re-sorption, gingival recession, and thus to exposure of the implant [2, 3, 4, 5].

Apicocoronal location of the implant (i.e. the fact how deep it is possible to place an implant) is a com-promise between esthetic and biological principles. The edge of the implant should be 1-2 mm apically from cemento-enamel junction of neighbouring teeth, or - in case of gingival recession - 2 mm from vestibular gingival margin of the planned restoration [3, 4].

Inclination of implant axis. Ideally, the implants should be placed in such a way, that the implant axis agrees with the axis of a natural tooth. In case the im-plant neck inclines vestibularly to an excessive degree, the condition may lead to the overload of the implant and to problems in prosthetic treatment. Most implant systems are able to compensate for the deviation of

UÂvod

ImplantaÂt je povazÏovaÂn za prodlouzÏenõ korunky a meÏl by tedy byÂt zaveden s ohledem na estetiku vyÂ-sledne proteticke praÂce. Toto pojetõ je znaÂme jako ¹re-storation-drivenª a je v kontrastu s drÏõÂveÏjsÏõÂm pojetõÂm, kdy se implantace rÏõÂdila cÏisteÏ nabõÂdkou kosti[1]. Jes-tlizÏe je v mõÂsteÏ plaÂnovane implantace nedostatek kosti nebo meÏkkyÂch tkaÂnõÂ, musõ byÂt tyto doplneÏny rÏõÂzenou tkaÂnÏovou regeneracõÂ. SpraÂvne trojrozmeÏrne umõÂsteÏnõ implantaÂtu je zaÂvisle na cÏtyrÏech parametrech [2, 3]. Im-plantaÂt musõ byÂt jednak umõÂsteÏn spraÂvneÏ ve 3 smeÏrech - meziodistaÂlnõÂm, vestibulooraÂlnõÂm a apikokoronaÂrnõÂm a pak musõ byÂt spraÂvneÏ angulovaÂn. Ve vsÏech trÏech roz-meÏrech rozlisÏujeme takzvane bezpecÏne (comfort) a ne-bezpecÏne (danger) zoÂny implantace. UmõÂsteÏnõ implan-taÂtu v bezpecÏne zoÂneÏ je podmõÂnkou dobre vyÂsledne estetiky implantace.

V meziodistaÂlnõÂm rozmeÏru jsou nebezpecÏne zoÂny uvazÏovaÂnyvzhledemksousedõÂcõÂmzubuÊm.VsoucÏasne dobeÏ byla sÏõÂrÏka teÏchto nebezpecÏnyÂch zoÂn prÏehodno-cena. DrÏõÂveÏjsÏõ publikace doporucÏovaly, aby implantaÂt byl zaveden nejmeÂneÏ 1 mm od povrchu korÏene sou-sednõÂho zubu. SoucÏasne studie vsÏak ukazujõÂ, zÏe v okolõ implantaÂtu se prÏirozeneÏ vytvaÂrÏõ naÂlevkovita resorpce kostiv rozsahu ne blõÂzÏe nezÏ 1,5 mm. S tõÂmto zjisÏteÏnõÂm pak byla prÏehodnocena nebezpecÏna zoÂna v meziodi-staÂlnõÂm rozmeÏru a stanovena na 1,5 mm od okraje zubu sousedõÂcõÂho s implantaÂtem [2, 3, 4] (obr. 1). S ohledem na tyto nebezpecÏne zoÂny musõ byÂt plaÂnovaÂna sÏõÂrÏe me-zery a velikost implantaÂtu.

VestibulaÂrnõ okraj implantaÂtu by meÏl byÂt umõÂsteÏn nejleÂpe 1 mm oraÂlnõÂm smeÏrem od spojnice maximaÂl-nõÂch konvexit sousedmaximaÂl-nõÂch zubuÊ. Od teÂto pomyslne linie 2 mm oraÂlneÏ se pak nachaÂzõ nebezpecÏna zoÂna implan-tace. ZavedenõÂimplantaÂtu palatinaÂlneÏjivede k narusÏenõ klenutõ gingivy a estetickeÂho prÏechodu krcÏku implan-taÂtu v krcÏek suprakonstrukce. UmõÂsteÏnõ implanimplan-taÂtu Obr. 1.NebezpecÏne (cÏerveneÂ) zoÂny implantace v meziodistaÂlnõÂm smeÏru.

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implant axis by means of angulated pillars (abutt-ments). Nevertheless, sometimes the excessive incli-nation of the fixture may result in impossible prosthetic treatment and explantation is necessary.

Both implant surgeon and orthodontist should eva-luate the overall situation prior to placement, and plan the implant type, size, shape as well as the type of su-praconstruction. Accumulation of negative factors leads to esthetically unfavorable results [3].

Material

The material included OPGs of 55 patients (they were patients of the Centre of implantology of Clinic of Stomatology, Medical Faculty of Charles University and University Hospital in Hradec KraÂloveÂ) with agene-sis of at least one maxillary lateral incisor; dental im-plants were introduced at the site of missing lateral in-cisors. All patients were treated with orthodontic fixed appliance before implantation, either at the Depart-ment of Orthodontics of the Clinic of Stomatology in Hradec KraÂlove or in private orthodontic practices. Im-plants were inserted after the finished growth of a pa-tient. Each patient had an OPG taken before the plan-ned replacement after the orthodontic treatment, when the space was prepared for the implantation of the left or right maxillary lateral incisor, and an OPG ta-ken at least 6 months after the procedure. OPGs pro-vided a distinct view of the roots of maxillary central in-cisor and canine.

In 55 pairs of OPGs we evaluated 79 places with missing maxillary lateral incisor. The sample included 20 men and 35 women. Bilateral agenesis was repre-sented by 24 cases, unilateral agenesis in 31 persons (11 on the left, 20 on the right side).

Implants of two manufacturers were used: Replace (Nobel Biocare, Sweden), the diameter of 3.5 and 4.3 mm respectively, 16 mm long; Impladent (Lasak, Czech Republic), either cylindrical, diameter of 2.9 mm and 16 mm long, or diameter of 3.7 mm and 14 mm, 16 mm, and 18 mm long, or conical ¹Accelª, dia-meter 4.4 mm, 16 mm long.

Method

OPGs were taken with a digital panoramic X-Ray Planmeca Pro Max Dimax3. Scans in .JPG format were copied to the programme ¹PC Dentª, and then printed in A4 format with a laser printer Konica Minolta Magi-color 4690 MF, scale = 1:155. The data were obtained through the OPGs evaluation made in two periods: at the end of orthodontic treatment prior to implantation (T1), and 6 or more months after the procedure (T2).

At T1, i.e. at the end of orthodontic treatment before the implantation, mesiodistal width of the space for the võÂce vestibulaÂrneÏ od teÂto linie vede k resorpci alveolaÂrnõÂ

kosti, vzniku recesu gingivy a tak obnazÏenõÂ implantaÂtu [2, 3, 4, 5].

ApikokoronaÂrnõ pozice implantaÂtu, tedy jak hluboko je mozÏne implantaÂt zaveÂst, je kompromisem mezi este-tickyÂmi a biologickyÂmi principy. Okraj implantaÂtu by meÏl byÂt umõÂsteÏn 1-2 mm apikaÂlneÏ od cementosklo-vinne hranice sousednõÂch zubuÊ nebo v prÏõÂpadeÏ gingi-vaÂlnõÂch recesuÊ 2 mm od vestibulaÂrnõÂho gingivaÂlnõÂho okraje plaÂnovane rekonstrukce [3, 4].

Sklon osy implantaÂtu. V ideaÂlnõÂm prÏõÂpadeÏ by implan-taÂty meÏly byÂt umõÂsteÏny tak, aby se osa implantaÂtu sho-dovala s osou prÏirozeneÂho zubu. Pokud je krcÏek fixtury vykloneÏn prÏõÂlisÏ vestibulaÂrneÏ, muÊzÏe to veÂst jednak k prÏe-tõÂzÏenõ implantaÂtu a jednak k potõÂzÏõÂm prÏiprotetickeÂm osÏetrÏenõÂ. VeÏtsÏina implantacÏnõÂch systeÂmuÊ je schopna kompenzovat pomocõ angulovanyÂch pilõÂrÏuÊ (abut-mentuÊ) odchylky sklonu osy fixtury. V extreÂmnõÂm prÏõÂ-padeÏ vsÏak prÏõÂlisÏne vykloneÏnõ fixtury muÊzÏe znamenat protetickou neosÏetrÏitelnost a nutnost jejõ explantace.

Implantolog iprotetik musõÂ spolecÏneÏ prÏed implan-tacõÂ zhodnotit situaci a naplaÂnovat typ, velikost, tvar implantaÂtu a typ suprakonstrukce. Kumulace neprÏõÂzni-vyÂch faktoruÊ vede k estetickeÂmu neuÂspeÏchu [3].

MateriaÂl

VyÂzkumnyÂm materiaÂlem byly ortopantomogramy 55 pacientuÊ s agenezõ alesponÏ jednoho hornõÂho po-strannõÂho rÏezaÂku, u kteryÂch byly na mõÂsta chybeÏjõÂcõÂch postrannõÂch rÏezaÂkuÊ zavedeny zubnõ implantaÂty. Jed-nalo se o pacienty ImplantologickeÂho centra Stomato-logicke kliniky LF UK a FN v Hradci KraÂloveÂ. VsÏichni pa-cienti byli prÏed implantacõ ortodonticky leÂcÏenifixnõÂm aparaÂtem, a to na oddeÏlenõ ortodoncie Stomatologicke kliniky LF UK a FN v Hradci KraÂlove nebo v ortodontic-kyÂch praxõÂch privaÂtnõÂch spolupracujõÂcõÂch ortodontistuÊ. Implantace byla provedena po ukoncÏenõ ruÊstu pa-cienta. VsÏichni pacienti meÏlizhotoveny ortopantomo-gram prÏed plaÂnovanou implantacõ v dobeÏ ukoncÏenõ ortodonticke leÂcÏby ve faÂzi prÏipravene mezery pro im-plantacihornõÂho leveÂho nebo praveÂho postrannõÂho rÏe-zaÂku a ortopantomogram alesponÏ 6 meÏsõÂcuÊ po implan-taciv mõÂsteÏ chybeÏjõÂcõÂho hornõÂho postrannõÂho rÏezaÂku. Na ortopantomogramu byly zrÏetelneÏ viditelne korÏeny hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku.

Z celkoveÂho pocÏtu 55 dvojic ortopantomogramuÊ hodnocenyÂch ve dvou cÏasovyÂch periodaÂch bylo hod-noceno 79 mõÂst s agenezõ hornõÂho postrannõÂho rÏezaÂku. Soubor tvorÏilo 20 muzÏuÊ a 35 zÏen. Oboustranna age-neze byla prÏõÂtomna ve 24 prÏõÂpadech, jednostranna ageneze v 31 prÏõÂpadech. Jednostranna ageneze byla v 11 prÏõÂpadech levostrannaÂ, ve 20 prÏõÂpadech pravo-strannaÂ.

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insertion of maxillary lateral incisor was measured in three lines (Fig. 2):

- line A - the connecting line between length of crowns of maxillary central incisor and canine;

- line B - the connecting line between cemento-enamel junctions (CEJ) of maxillary central incisor and canine;

- line C - the connecting line between apexes of ma-xillary central incisor and canine.

At T2, i.e. at least 6 months after the implantation, the following parameters were measured (Fig. 3):

- the distance between the inserted implant and maxillary central incisor in lines B and C;

- the distance between the inserted implant and maxillary canine in lines B and C;

- the relationship to danger zone in lines B and C. At T1 and T2 we determined the extent of horizontal projection magnification of individual OPGs in the area of maxillary incisors by means of measurement of the width of central incisor next to the space at T1 and T2, and diameter of an implant at T2. The reference va-lue was the implant diameter because the dimension was known. From the actual and measured implant diameter the extent of horizontal projection magnifica-tion of OPG at T2 was calculated. Then we measured the width of central incisor next to the gap at T1 and T2. By means of known coefficient of magnification the actual width of incisor was calculated. From the width of incisor measured at T1 and its actual calcula-ted width at T2 the degree of distortion of OPG at T1 was determined.

In each radiogram the lines A, B and C were drawn at T1 and T2 (Fig. 2, 3). We measured mesiodistal width of the space at lines A,B and C at T1 and T2. Further we measured the distance of an implant from maxillary central incisor and canine at lines B, C at T2. The values U pacientuÊ byly zavedeny implantaÂty 2 vyÂrobcuÊ, a to

sÏveÂdske implantaÂty Replace od firmy Nobel Biocare pruÊmeÏru 3,5 a 4,3 mm, oba deÂlky 16 mm, a cÏeske i m-plantaÂty Impladent od firmy Lasak, a to imm-plantaÂty vaÂl-cove pruÊmeÏru 2,9 mm a deÂlky 16 mm, a daÂle pruÊmeÏru 3,7 mm o deÂlkaÂch 14 mm, 16 mm, 18 mm a implantaÂty koÂnicke ¹Accelª pruÊmeÏru 4,4 mm a o deÂlce 16 mm.

Metodika

Ortopantomogramy byly porÏõÂzeny digitaÂlnõÂm rent-genografem Planmeca Pro Max s Dimax3. Rentge-nove snõÂmky byly ve formaÂtu JPG kopõÂrovaÂny do pro-gramu ¹PC Dentª, a odtud byly naÂsledneÏ vytisÏteÏny na sÏõÂrÏku kancelaÂrÏskeÂho papõÂru velikosti A4 laserovou tis-kaÂrnou Konica Minolta Magicolor 4690 MF v meÏrÏõÂtku 1:155. Data pak byla zõÂskaÂna hodnocenõÂm ortopanto-mogramuÊ ve dvou cÏasovyÂch periodaÂch: na konciorto-donticke leÂcÏby prÏed implantacõ (v cÏase T1) a 6 a võÂce meÏsõÂcuÊ po implantaci (v cÏase T2).

V cÏase T1, tj. na konciortodonticke leÂcÏby prÏed im-plantacõÂ, byla meÏrÏena meziodistaÂlnõ sÏõÂrÏe prÏipravene mezery pro implantaci hornõÂho postrannõÂho rÏezaÂku ve trÏech liniõÂch (obr. 2):

- linie A - spojnice deÂlky korunek hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku;

- linie B - spojnice cementosklovinnyÂch hranic (CEJ) hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku;

- linie C - spojnice apexuÊ hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku.

V cÏase T2, tj. 6 a võÂce meÏsõÂcuÊ po implantaci, byla meÏ-rÏena (obr. 3): :

- vzdaÂlenost zavedeneÂho implantaÂtu od hornõÂho strÏednõÂho rÏezaÂku v liniõÂch B a C

- vzdaÂlenost zavedeneÂho implantaÂtu od hornõÂho sÏpi cÏaÂku v liniõÂch B a C;

- vztah k nebezpecÏne zoÂneÏ implantace danger zone, v liniõÂch B a C.

Obr. 2.Linie A (cÏerveneÏ), B (oranzÏoveÏ), C (modrÏe) v cÏase T1. Popis liniõÂ v textu.

Fig. 2.Line A (red), B (orange), C (blue) at T1. Description of individual lines - see the text.

Obr. 3.Linie A (cÏerveneÏ), B (oranzÏoveÏ), C (modrÏe) v cÏase T2. Popis liniõÂ v textu.

Fig. 3.Line A (red), B (orange), C (blue) at T2. Description of individual lines - see the text.

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measured were at T1 and T2 multiplied with the esta-blished coefficient of distortion x(T1), x(T2).

Results

The mean value of projection magnification of OPG was 125±7%, minimum 105%, maximum 138%. The pair t-test did not prove statistically significant change in projection magnification of the area of maxillary inci-sors in [%] at T1 and T2. F-test for comparison of the equality of two dispersions did not prove statistically significant difference between the dispersion of pro-jection magnification in the area of maxillary incisors in [%] at T1 and T2.

The mean value of mesiodistal width of the space prepared for the replacement of maxillary lateral inci-sor on the connecting line between CEJ of maxillary central incisor and canine was 6.93±0.62 mm, and on the connecting line between apexes of maxillary central incisor and canine (line C) 9.20±0.80 mm. The mean value of the width of the space on the con-necting line between CEJ of maxillary central incisor and canine corresponds to the value recommended in literature [2, 3, 4] (Fig. 4).

The difference of the width between the magnified and actual width of the space was 1.53+0.44 mm on line A, 1.66±0.48 on line B, and 2.22±0.66 mm on line C (Fig. 5). Pair t-test proved statistically significant dif-ference between magnified and actual width of the gaps in the three lines.

The space was always narrower on the connecting line between maxillary central incisor and canine than on the connecting line between apexes of maxillary central incisor and canine - the mean difference was 2.20±0.54 mm, with the minimum of 1.13 mm. This fact proves the correspondence or divergency of the roots of central incisor and canine. The space, which is mesiodistally available for the future implant (com-fort zone) [10, 15] was calculated by means of subtrac-V cÏase T1 a T2 byla zjisÏteÏna mõÂra horizontaÂlnõÂho

pro-jekcÏnõÂho zveÏtsÏenõ jednotlivyÂch ortopantomogramuÊ v oblastihornõÂch rÏezaÂkuÊ pomocõ meÏrÏenõ sÏõÂrÏky strÏednõÂho rÏezaÂku sousedõÂcõÂho s mezerou v cÏase T1 a T2 a pruÊ-meÏru zavedeneÂho implantaÂtu v cÏase T2. ReferencÏnõ hodnotou byl pruÊmeÏr implantaÂtu jako znaÂmy rozmeÏr. Ze znalostiskutecÏneÂho a nameÏrÏeneÂho pruÊmeÏru i m-plantaÂtu byla vypocÏõÂtaÂna mõÂra horizontaÂlnõÂho projekcÏ-nõÂho zveÏtsÏenõ ortopantomogramu v cÏase T2. NaÂsledneÏ bylo provedeno meÏrÏenõ sÏõÂrÏky strÏednõÂho rÏezaÂku souse-dõÂcõÂho s mezerou v cÏase T1 a T2. Ze znalostikoefi-cientu zveÏtsÏenõ byla z nameÏrÏene sÏõÂrÏky rÏezaÂku zjisÏteÏna jeho skutecÏna sÏõÂrÏka. Ze zmeÏrÏene sÏõÂrÏky strÏednõÂho rÏezaÂku v cÏase T1 a jeho vypocÏõÂtane skutecÏne sÏõÂrÏky v cÏase T2 byla vypocÏõÂtaÂna mõÂra zkreslenõ OPG v cÏase T1.

Na kazÏdeÂm rentgenogramu byly v cÏase T1 a T2 za-kresleny linie A, B a C (obr. 2, 3). Byla zmeÏrÏena meziodi-staÂlnõ sÏõÂrÏka mezery v liniõÂch A, B, C v cÏase T1 a v cÏase T2. DaÂle byla meÏrÏena vzdaÂlenost implantaÂtu od hor-nõÂho strÏedhor-nõÂho rÏezaÂku a od sÏpi cÏaÂku v liniõÂch B, C v cÏase T2. NameÏrÏene hodnoty byly v prÏõÂslusÏnyÂch cÏasovyÂch uÂsecõÂch T1, T2 naÂsobeny vypocÏõÂtanyÂm koeficientem zkreslenõ x(T1), x(T2).

VyÂsledky

PruÊmeÏrna hodnota projekcÏnõÂho zveÏtsÏenõ ortopanto-mogramu byla 125±7 % s minimem 105 % a maximem 138 %. PaÂrovy t-test neprokaÂzal statisticky vyÂznam-nou zmeÏnu projekcÏnõÂho zveÏtsÏenõ oblastihornõÂch rÏe-zaÂkuÊ v [%] v cÏase T1 a v cÏase T2. F-testem pro porov-naÂnõ shody dvou rozptyluÊ nebyl zjisÏteÏn statisticky vyÂ-znamny rozdõÂl mezirozptylem hodnot projekcÏnõÂho zveÏtsÏenõ v oblastihornõÂch rÏezaÂkuÊ v [%] v cÏase T1 a v cÏase T2.

PruÊmeÏrna meziodistaÂlnõ sÏõÂrÏka prÏipravene mezery pro implantaci hornõÂho postrannõÂho rÏezaÂku byla na spojnici cementosklovinnyÂch hranic hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku pruÊmeÏrneÏ 6,93±0,62 mm a na

spoj-14 13 12 11 10 9 8 7 6 5 mm A − T1_x B − T1_x C − T1_x A − T1 B − T1 C − T1 mm Diff A Diff B Diff C 0,5 1,0 1,5 2,0 2,5 3,0 3,5

Obr. 4. SÏõÂrÏka prÏipravenyÂch mezer v liniõÂch A, B a C v projekcÏnõÂm zveÏt-sÏenõÂ (x) a bez zveÏtzveÏt-sÏenõÂ

Fig. 4. Width of spaces for an implant in lines A, B and C in projection magnification (x) and without magnification

Obr. 5. RozdõÂl v sÏõÂrÏce (Diff) mezi projekcÏneÏ zveÏtsÏenou a skutecÏnou meziodistaÂlnõÂ sÏõÂrÏkou mezery pro implantaÂt v liniõÂch A, B a C. Fig. 5. Difference in width (Diff) between magnified and actual mesio-distal width of the space for an implant in lines A, B and C.

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ting both danger zones from the width of the space in line B. The choice of maximum diameter of the implant was limited by the mesiodistal width of the space on the connecting line between CEJs of maxillary central incisor and canine.

The minimum required width of danger zone was set to 1.5 mm and 1.0 mm. Table 1, figure 6 give statistical characteristics of the extent of central position and the extent of dispersion of mesiodistal widths of comfort zone of the spaces at T1, for selected mesiodistal widths of danger zone in line B before and after the cor-rection of projection horizontal magnification.

Provided that the danger zone (width of 1.0 mm) re-mains intact, in our sample of patients the implants of the diameter 2.9 mm may be inserted in 100% of cases, the implants of the diameter 3.5 mm in 100% of cases, and those with the diameter of 4.4 mm in 77% of cases. Provided that the danger zone (width of 1.5 mm) re-mains intact, the implants of the diamater 2.9 mm may be inserted in 96% of cases, the implants of the diame-ter of 3.5 mm in 75% of cases, the diamediame-ter of 3.7 mm in 62%, the diameter of 4.3 mm in 27%, and those of the diameter of 4.4 mm only in 20% of cases (Fig. 7). nici apexuÊ hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku (linie C)

pruÊmeÏrneÏ 9,20±0,80 mm. PruÊmeÏrna sÏõÂrÏka mezery na spojnici cementosklovinnyÂch hranic hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku je v souladu s literaÂrneÏ doporucÏenou hodnotou [2, 3, 4] (obr. 4)

RozdõÂl v sÏõÂrÏce meziprojekcÏneÏ zveÏtsÏenou a skutecÏ-nou sÏõÂrÏkou mezery byl v linii A pruÊmeÏrneÏ 1,53±0,44 mm, v linii B pruÊmeÏrneÏ 1,66±0,48 mm a v linii C pruÊ-meÏrneÏ 2,22±0,66 mm (obr. 5). PaÂrovy t-test take pro-kaÂzal statisticky vyÂznamnou odlisÏnost projekcÏneÏ zveÏt-sÏenyÂch a skutecÏnyÂch sÏõÂrÏek mezer ve vsÏech trÏech sle-dovanyÂch liniõÂch.

Ve vsÏech prÏõÂpadech byla prÏipravena mezera uzÏsÏõ na spojnici cementosklovinnyÂch hranic hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku, nezÏ na spojnici apexuÊ hornõÂho strÏed-nõÂho rÏezaÂku a sÏpi cÏaÂku, a to pruÊmeÏrneÏ o 2,28±0,54 mm s minimem 1,13 mm. To sveÏdcÏõ o paraleliteÏ nebo diver-gencikorÏenuÊ strÏednõÂho rÏezaÂku a sÏpi cÏaÂku. Prostor v me-zerÏe, ktery je meziodistaÂlneÏ k dispozici pro budoucõ im-plantaÂt (comfort zone) [10, 15] byl kalkulovaÂn odecÏte-nõÂm obou danger zone od sÏõÂrÏky prÏipravene mezery v linii B. U sledovaneÂho souboru byla ve vsÏech prÏõÂpa-dech limitujõÂcõÂm faktorem pro volbu maximaÂlnõÂho pruÊ-meÏru zavaÂdeÏneÂho implantaÂtu meziodistaÂlnõ sÏõÂrÏka prÏi-pravene mezery na spojnici cementosklovinnyÂch hra-nic hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku.

MinimaÂlnõ zÏaÂdana sÏõÂrÏka danger zone byla postupneÏ stanovena na 1,5 mm a 1,0 mm. Statisticke charakte-ristiky mõÂry strÏednõ polohy a mõÂry rozptylu meziodistaÂl-nõÂch sÏõÂrÏek comfort zone prÏipravovanyÂch mezer v cÏase T1 jsou pro zvolene meziodistaÂlnõÂsÏõÂrÏky danger zone v li-nii B prÏed korekcõ ipo korekciprojekcÏnõÂho horizontaÂl-nõÂho zveÏtsÏenõ uvedeny v Tab. 1 na obr. 6.

U sledovaneÂho souboru mohly byÂt za prÏedpokladu uchovaÂnõ nedotcÏene danger zone o sÏõÂrÏce 1,0 mm zave-deny implantaÂty o pruÊmeÏru 2,9 mm ve 100 % prÏõÂpaduÊ, o pruÊmeÏru 3,5 mm take ve 100 % prÏõÂpaduÊ, o pruÊmeÏru 4,4 mm v 77 % prÏõÂpaduÊ. PrÏiprÏedpokladu uchovaÂnõ ne-dotcÏene danger zone o sÏõÂrÏce 1,5 mm mohly byÂt zave-deny implantaÂty o pruÊmeÏru 2,9 mm v 96 % prÏõÂpaduÊ, o pruÊmeÏru 3,5 mm v 75 % prÏõÂpaduÊ, o pruÊmeÏru 3,7mm v 62 % prÏõÂpaduÊ, o pruÊmeÏru 4,3mm ve 27 % prÏõÂ-paduÊ a o pruÊmeÏru 4,4 mm jen ve 20 % prÏõÂprÏõÂ-paduÊ (obr. 7). V nasÏem souboru jsme hodnotili na ortopantomo-gramech zhotovenyÂch minimaÂlneÏ 6 meÏsõÂcuÊ ( v cÏase

Danger

zone N Mean S.D. Min. Med. Max. Range

CZ_B_x 1 79 6,59 0,74 4,8 6,5 8,2 3,4

CZ_B 1 79 4,93 0,62 3,77 4,9 6,64 2,87

CZ_B_x 1,5 79 5,59 0,74 3,8 5,5 7,2 3,4

CZ_B 1,5 79 3,93 0,62 2,77 3,9 5,64 2,87

Tab. 1.MeziodistaÂlnõÂ sÏõÂrÏka comfort zone v zaÂvislosti na volbeÏ sÏõÂrÏky danger zone v [mm] v cÏase T1

Tab. 1.Mesiodistal width of comfort zone related to the selected width of danger zone in [mm] at T1

CZ_B_x; CZ_B ... zdaÂnliva (x) a skutecÏna meziodistaÂlnõ sÏõÂrÏka comfort zone v mm, seeming (x) and real mesiodistal width of comfort zone in mm

Obr. 6.Velikost comfort zone v zaÂvislosti na zvolene sÏõÂrÏce danger zone. CZ_B_x (1,0); CZ_B (1,0); CZ_B_x (1,5); CZ_B (1,5) meziodi-staÂlnõ sÏõÂrÏka comfort zone (CZ) prÏipravovanyÂch mezer pro zvolene meziodistaÂlnõ sÏõÂrÏky danger zone 1,0 mm a 1,5 mm v linii B prÏed ko-rekcõ (x) ipo korekciprojekcÏnõÂho horizontaÂlnõÂho zveÏtsÏenõÂ

Fig. 6.Size of comfort zone related to the selected width of danger zone. CZ_B_x (1,0); CZ_B (1,0); CZ_B_x (1,5); CZ_B (1,5) mesiodi-stal width of comfort zone (CZ) of the spaces for the selected widths of danger zone 1.0 mm a 1.5 mm in line B before correction (x) and after the correction of projection horizontal magnification

mm CZ_B_x (1,0) CZ_B (1,0) CZ_B_x (1,5) CZ_B (1,5) 3,2 4,0 4,8 5,6 6,4 7,2 8,0

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In our sample, on OPGs taken at least 6 months (T2) after implantation, we evaluated possible disruption of the implantation danger zone (Tab.2).Apparent dan-ger zone, the width of 1.0 mm, as seen in projection magnification without calibration, remainedintactby the implant of a given diameterin all 79cases obser-ved (100%), and in all lines obserobser-ved, i.e. on the con-necting line between CEJs of maxillary central incisor and canine - between incisor and implant, as well as between implant and canine; and on the connecting line of apexes of maxillary central incisor and canine between incisor and implant as well as between im-plant and canine. Actual danger zone, the width of 1.0 mm after calibration of OPGs with magnification, remained intact by the implant of a given diameter in 78 cases observed (99%), in all three lines monitored. In one case (1%) the actual danger zone, the width of 1.0 mm, was disrupted on the connecting line between CEJs of maxillary central incisor and canine, and this was between incisor and implant, by - 0.01 mm, i.e. beyond measuring error.

Apparent danger zone, the width of 1.5 mm without calibration through magnification, as well as actual danger zone, the width of 1.5 mm after OPG calibration through magnification remains intact by the implant of the given diameter in all 79 observed cases (100%) in the line on the connecting line of apexes of maxillary central incisor and canine both between the incisor and the implant and between the implant and the ca-nine. However, on the line on the connecting line of CEJs of maxillary central incisor and canine the width of danger zone 1.5 mmbetween the implant T2) po implantaci prÏõÂpadne narusÏenõ nebezpecÏneÂ

(dan-ger) zoÂny implantace (Tab. 2).ZdaÂnliva danger zone o sÏõÂrÏce 1,0 mm, jak se jevõ v projekcÏnõÂm zveÏtsÏenõ bez kalibrace zveÏtsÏenõÂm, byla nedotcÏena implantaÂtem pouzÏiteÂho pruÊmeÏruve vsÏech 79pozorovanyÂch prÏõÂpa-dech (100 %), a to ve vsÏech sledovanyÂch liniõÂch, tj. jak na spojnici cementosklovinnyÂch hranic hornõÂho strÏed-nõÂho rÏezaÂku a sÏpi cÏaÂku mezirÏezaÂkem a implantaÂtem imeziimplantaÂtem a sÏpi cÏaÂkem,a na spojnici apexuÊ hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku mezirÏezaÂkem a im-plantaÂtem imeziimim-plantaÂtem a sÏpi cÏaÂkem. SkutecÏna danger zone o sÏõÂrÏce 1,0 mm po kalibraci ortopantomo-gramu zveÏtsÏenõÂm byla nedotcÏena implantaÂtem pouzÏi-teÂho pruÊmeÏru v 78 pozorovanyÂch prÏõÂpadech (99 %), a to ve vsÏech trÏech sledovanyÂch liniõÂch. V jednom po-zorovaneÂm prÏõÂpadeÏ (1 %) byla skutecÏna danger zone

Implant size [mm] N DZ = 1,5 mm (x) DZ = 1,0 mm (x) 2,9 4 0 0% 0 0% 3,5 20 0 0% 0 0% 3,7 34 0 0% 0 0% 4,3 2 0 0% 0 0% 4,4 19 0 0% 0 0% CELKEM 79 0 0% 0 0% Implant size [mm] DZ = 1,5 mm DZ = 1,0 mm 2,9 4 2 50% 0 0% 3,5 20 9 45% 0 0% 3,7 34 14 41% 0 0% 4,3 2 0 0% 0 0% 4,4 19 13 68% 0 0% CELKEM 79 38 48% 0 0%

Tab. 2.CÏetnost a relativnõ cÏetnost indikace skutecÏneÏ pouzÏiteÂho pruÊmeÏru implantaÂtu, ktera nerespektovala zachovaÂnõ nedotcÏene danger zone urcÏi te sÏõÂrÏky

Tab. 2.Prevalence and relative prevalence of the indication for the actually used diameter of an implant which did not respect preservation of intact danger zone of a given width

DZ ... sÏõÂrÏka danger zone zdaÂnliva na OPG (x) a skutecÏnaÂ, seeming (x) and real width of the danger zone in OPG

100 90 80 70 60 50 40 30 20 10 % 2,9 3,5 3,7 4,3 4,4 Implant size (diameter) [mm]

DZ 1,5 mm

Obr. 7.MaximaÂlnõ pouzÏitelny pruÊmeÏr implantaÂtu v zaÂvislosti na plaÂ-novane sÏõÂrÏce danger zone

Fig. 7.Maximum possible diameter of an implant related to the plan-ned width of danger zone

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and adjacent teethremained intact in 30 cases out of 79 (38%). The danger zone 1.5 mm was disrupted by the implant in 49 cases out of 79 (62%): danger zone 1.5 mm was disrupted mesially between central incisor and the implant in 16 cases (20%), distally in 6 cases (8%), and both mesially and distally in 27 cases (34%). In 30 cases out of 79 (38%) the width of danger zone 1.5 mm between the implant and adjacent teeth remained intact.

Actual width of danger zone 1.5 mmwas respec-ted in indication only in 41 cases. Thus, itwas not re-spected in 38 cases (48%): in the implant of the dia-meter 2.9 mm in 2 cases out of 4 (50%); in the implant of the diameter 3.5 mm in 9 cases out of 20 (45%); in the implant of the diameter 3.7 mm in 14 cases out of 34 (41%); in the implant of the diameter 4.4 mm in 13 cases out of 19 (38%). Danger zone 1.5 mm was dis-rupted by the implant in 49 cases out of 79 (62%): me-sially between central incisor and the implant in 16 ca-ses (20%); distally in 6 caca-ses (8%), and both mesially and distally in 27 cases (34%). Mesial danger zone 1.5 mm was disrupted in 43 cases on the average by -0.17±0.12 mm. Distal danger zone was disrupted in 33 cases by -0.20±0.12 mm on the average.

To determine the strength of the association bet-ween disruption of danger zone 1.5 mm betbet-ween the implant and adjacent teeth on the level on the connec-ting line of CEJs of maxillary central incisor and canine mesially between incisor and the implant, and distally between the implant and canine, we correlated - by means of Pearson`s linear correlation coefficient and determination coefficient - the following factors: the extent of horizontal projection magnification in [%] in the area of maxillary incisors in a diagnostic OPG taken before implantation at T1; apparent mesiodistal width of the space (in OPG) prepared for the insertion of ma-xillary lateral incisor; actual (calibrated) mesiodistal width of the space prepared for the insertion of maxil-lary lateral incisor; indication for the implant with a dia-meter larger than the available width of comfort zone provided that danger zone 1.5 mm remained intact; the implant diameter used; change in the mesiodistal width of the space at T1®T2, i.e.potential orthodontic movements after replacement.

With Pearson`s linear correlation coefficientrto de-termine the association with disruption of danger zone 1.5 mm on the B level we determined very strong and statistically significant correlation with the indication of wider diameter of the implant than the available width of comfort zone providing that danger zone 1.5 mm remained intact, both mesially between incisor and the implant (r = 0.90; p<0.001), and distally bet-ween the implant and canine (r = 0.87; p¬0.001). The disruption of danger zone 1.5 mm on the level B was o sÏõÂrÏce 1,0 mm narusÏena na spojnici cementosklovinneÂ

hranice hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku, a to mezi rÏezaÂkem a implantaÂtem o -0,01 mm, tedy za hranicõÂ chyby meÏrÏenõÂ.

ZdaÂnliva danger zone o sÏõÂrÏce 1,5 mm bez kalibrace zveÏtsÏenõÂm iskutecÏna danger zone o sÏõÂrÏce 1,5 mm po kalibraci ortopantomogramu zveÏtsÏenõÂm zuÊstaly nedo-tcÏeny implantaÂtem pouzÏiteÂho pruÊmeÏru ve vsÏech 79 po-zorovanyÂch prÏõÂpadech (100 %) v linii na spojnici apexuÊ hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku mezirÏezaÂkem a im-plantaÂtem imeziimim-plantaÂtem a sÏpi cÏaÂkem. OvsÏemv li-nii na spojnici cementosklovinnyÂch hranichornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku byla sÏõÂrÏka danger zone 1,5 mmmeziimplantaÂtem a sousednõÂmizuby zacho-vaÂna ve 30 prÏõÂpadechze79 (38 %). K narusÏenõ danger zone 1,5 mm implantaÂtem dosÏlo celkem ve 49 prÏõÂpa-dech ze 79 (62 %), z toho byla danger zone 1,5 mm na-rusÏena jen meziaÂlneÏ mezistrÏednõÂm rÏezaÂkem a implan-taÂtem v 16 prÏõÂpadech (20 %), jen distaÂlneÏ v 6 prÏõÂpadech (8 %) a oboustranneÏ ve 27 prÏõÂpadech (34 %). Ve 30 prÏõÂ-padech ze 79 (38 %) byla sÏõÂrÏka danger zone 1,5 mm meziimplantaÂtem a sousednõÂmizuby nedotcÏena.

SkutecÏna sÏõÂrÏka danger zone 1,5 mmpak byla re-spektovaÂna prÏiindikacipouze v 41 prÏõÂpadech.Nebyla

tedy respektovaÂna ve 38 prÏõÂpadech (48 %), z toho u pruÊmeÏru implantaÂtu 2,9 mm ve 2 prÏõÂpadech ze 4 (50 %), u pruÊmeÏru implantaÂtu 3,5 mm v 9 prÏõÂpadech z 20 (45 %), u pruÊmeÏru implantaÂtu 3,7 mm ve 14 prÏõÂpa-dech z 34 (41 %) a u pruÊmeÏru implantaÂtu 4,4 mm ve 13 prÏõÂpadech z 19 (68 %). V linii na spojnici cementos-klovinnyÂch hranic hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku byla sÏõÂrÏka danger zone 1,5 mm meziimplantaÂtem a sou-sednõÂmizuby zachovaÂna nedotcÏena ve 30 prÏõÂpadech ze 79 (38 %). K narusÏenõÂ danger zone 1,5 mm implantaÂtem dosÏlo v celkem 49 prÏõÂpadech ze 79 (62 %), z toho byla danger zone 1,5 mm narusÏena jen meziaÂlneÏ mezistrÏed-nõÂm rÏezaÂkem a implantaÂtem v 16 prÏõÂpadech (20 %), jen distaÂlneÏ v 6 prÏõÂpadech (8 %) a oboustranneÏ ve 27 prÏõÂpa-dech (34 %). MeziaÂlnõÂ danger zone 1,5 mm byla v teÏchto 43 prÏõÂpadech narusÏena pruÊmeÏrneÏ o -0,17±0,12 mm. DistaÂlnõÂ danger zone 1,5 mm byla v teÏchto 33 prÏõÂpadech narusÏena pruÊmeÏrneÏ o -0,20±0,12 mm.

Ke zjisÏteÏnõÂ sõÂly asociace mezi narusÏenõÂm danger zone 1,5 mm meziimplantaÂtem a sousednõÂmizuby v li-nii na spojnici cementosklovinnyÂch hranic hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku meziaÂlneÏ mezirÏezaÂkem a implantaÂtem a distaÂlneÏ meziimplantaÂtem a sÏpi cÏaÂkem byly pomocõÂ Pearsonova koeficientu lineaÂrnõÂ korelace a koeficientu determinace korelovaÂny s rozdõÂlem mezi dostupnou comfort zone vlinii B a sÏõÂrÏkou pruÊrÏezu zvo-leneÂho implantaÂtu v [mm] naÂsledujõÂcõÂ faktory: mõÂra ho-rizontaÂlnõÂho projekcÏnõÂho zveÏtsÏenõÂ v [%] v oblastihor-nõÂch rÏezaÂkuÊ na diagnostickeÂm ortopantomogramu zhotoveneÂm prÏed implantacõÂ v cÏase T1, zdaÂnlivaÂ

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also strongly associated with the actual (calibrated) mesiodistal width of the space for the implant, both mesially (r = 0.75; p <0.001), and distally (r = -0.69; p <0.001). Mean values of correlation were found bet-ween the disruption of danger zone 1.5 mm and the extent of horizontal projection magnification in the area of maxillary incisors, on a diagnostic OPG (me-sially: r = -0.57; p<0.001; distally: r = -0.39; p<0.001), and with apparent mesiodistal width of the space on OPG taken before the implantation (mesially: r = 0.37; p<0.01; distally: r = 0.43; p<0.001). Correla-tion between the disrupCorrela-tion of danger zone 1.5 mm on the level B and the diameter of the implant, or the change in mesiodistal width of the gap at T1®T2; i.e. potentional orthodontic movements after the implan-tation, was not proved.

Determination coefficientr2expressing the

propor-tion of explained variability to overall variability indica-tes that the indication of the implant with diameter lar-ger than the available width of comfort zone providing danger zone 1.5 mm remained intact explains 81% disruptions of danger zone 1.5 mm on the level B me-sially between incisor and the implant, and 75% di-stally. The remaining 20%, resp.25% of variability re-sult from other factors (Fig. 8, 9).

The prepared available mesiodistal width of comfort zone in line B (i.e. on the connecting line of CEJs bet-ween maxillary central incisor and canine) with hypo-thetically established width of danger zone 1.5 mm by indication of the implant with diameter larger than the available width of comfort zone was exceeded in 38 ca-ses, by 0.30±0.25 mm on the average, with the mini-mum of 0.01 mm and the maximini-mum of 1.00 mm. In 8 ca-ses the width was exceeded more than 0.50 mm. meziodistaÂlnõÂ sÏõÂrÏka mezery na ortopantomogramu

prÏi-pravene pro implantaci hornõÂho postrannõÂho rÏezaÂku, skutecÏna (kalibrovanaÂ) meziodistaÂlnõ sÏõÂrÏka mezery prÏi-pravene pro implantaci hornõÂho postrannõÂho rÏezaÂku, indikace sÏi rsÏõÂho pruÊrÏezu implantaÂtu nezÏ byla dostupna sÏõÂrÏka comfort zone prÏiprÏedpokladu zachovaÂnõ danger zone 1,5 mm, pouzÏity pruÊmeÏr implantaÂtu, zmeÏna meziodistaÂlnõ sÏõÂrÏky mezery v cÏase T1®T2, tj. potencio-naÂlnõ poimplantacÏnõ ortodonticke pohyby.

PearsonovyÂm koeficientem lineaÂrnõ korelace r ke zjisÏteÏnõ sõÂly asociace s narusÏenõÂm danger zone 1,5 mm v linii B byla zjisÏteÏna velmisilna a statisticky vysoce vyÂznamna korelace s indikacõ sÏi rsÏõÂho pruÊrÏezu implantaÂtu nezÏ byla dostupna sÏõÂrÏka comfort zone pro prÏedpoklad zachovaÂnõ danger zone 1,5 mm, a to jak meziaÂlneÏ mezirÏezaÂkem a implantaÂtem (r = 0,90; p <0,001), tak distaÂlneÏ meziimplantaÂtem a sÏpi cÏaÂkem (r = 0,87; p<0,001). NarusÏenõÂdanger zone 1,5 mm v linii B bylo take silneÏ asociovaÂno se skutecÏnou (kalibrova-nou) meziodistaÂlnõ sÏõÂrÏkou mezery prÏipravene pro im-plantaci, a to take jak meziaÂlneÏ (r = 0,76; p< 0,001), tak idistaÂlneÏ (r = -0,69; p<0,001). Pouze strÏednõ hod-noty korelace byly zjisÏteÏny mezinarusÏenõÂm danger zone 1,5 mm a mõÂrou horizontaÂlnõÂho projekcÏnõÂho zveÏt-sÏenõ v oblastihornõÂch rÏezaÂkuÊ na diagnostickeÂm orto-pantomogramu (meziaÂlneÏ r = -0,57; p<0,001; distaÂlneÏ r = -0,39; p<0,001 ) a se zdaÂnlivou meziodistaÂlnõ sÏõÂrÏkou mezery na ortopantomogramu zhotoveneÂm prÏed im-plantacõ (meziaÂlneÏ r = 0,37; p<0,01; distaÂlneÏ r = 0,43; p < 0,001 ). Korelace mezinarusÏenõÂm danger zone 1,5 mm v linii B a pouzÏityÂm pruÊmeÏrem implantaÂtu ani zmeÏnou meziodistaÂlnõ sÏõÂrÏky mezery v cÏase T1®T2, tj. potencionaÂlnõÂmipoimplantacÏnõÂmiortodontickyÂmipo-hyby nebyla prokaÂzaÂna.

1,00 0,75 0,50 0,25 0,00 −0,25 −0,50 − 1,0 − 0,5 0,0 0,5 1,0 1,5 2,0 Def_CZ_T1 [mm] Def_Bm [mm] r = − 0,900 r2 = 81% 1,00 0,75 0,50 0,25 0,00 −0,25 −0,50 − 1,0 − 0,5 0,0 0,5 1,0 1,5 2,0 Def_CZ_T1 [mm] Def_Bm [mm] r = − 0,865 r2 = 75%

Obr. 8. Asociace mezi narusÏenõÂm danger zone 1,5 mm meziaÂlneÏ mezirÏezaÂkem a implantaÂtem (Def_Bm) a indikacõÂ sÏi rsÏõÂho pruÊrÏezu im-plantaÂtu nezÏ byla sÏõÂrÏka comfort zone pro danger zone 1,5 mm (Def_CZ_T1)

Fig. 8.Association between disruption of danger zone 1.5 mm me-sially between incisor and an implant (Def_Bm) and the indication of an implant diameter larger than the width of comfort zone for danger zone 1.5 mm (Def_CZ_T1)

Obr. 9.Asociace mezi narusÏenõÂm danger zone 1,5 mm distaÂlneÏ mezi implantaÂtem a sÏpi cÏaÂkem (Def_Bd) a indikacõÂ sÏi rsÏõÂho pruÊrÏezu implan-taÂtu nezÏ byla sÏõÂrÏka comfort zone pro danger zone 1,5 mm (Def_CZ_T1)

Fig. 9.Association between disruption of danger zone 1.5 mm di-stally between an implant and canine (Def_Bd) a the indication of an implant diameter larger than the width of comfort zone for danger zone 1.5 mm (Def_CZ_T1)

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To determine the strength of the association bet-ween horizontal projection magnification in the area of maxillary incisors in OPGs taken at T1, i.e. before the introduction of an implant, and the indicated width of the implant diameter, that takes into consideration danger zone, we correlated - with Pearson`s linear cor-relation coefficient and determination coefficient - the extent of horizontal projection magnification in [%] and the difference between the available comfort zone in line B and the width of the chosen implant diameter in [mm].

Pearson`s linear correlation coefficient r which is used to determine the strength of the association bet-ween horizontal projection magnification in [%] in the area of maxillary incisors in OPGs taken at T1, i.e. be-fore the insertion of an implant, and the difference bet-ween the available comfort zone in the level B and the width of cross-section of the chosen implant in [mm], proved substantial and statistically significant correla-tion of horizontal projeccorrela-tion magnificacorrela-tion of the area of incisors in OPG and the difference between the avai-lable comfort zone and the width of cross-section of the selected implant (r = -0.56; p¬0.001). See Fig.10.

Determination coefficient r2 expressing the propor-tion of the variability explained to overall variability in-dicates that the extent of horizontal projection magni-fication in the area of incisors in OPG explains only 31% of the mesiodistal differences in width between the comfort zone available and the diameter of the se-lected implant. The remaining 70% of variability result from other factors.

Discussion

Radiographic examination is the fundamental exa-mination in implant surgery used to determine both quantity and quality of alveolar bone. Analogue and di-Koeficient determinacer2vyjadrÏujõÂcõÂ pomeÏr

vysveÏ-tlene variability k celkove variabiliteÏ indikuje, zÏe indi-kace sÏirsÏõÂho pruÊrÏezu implantaÂtunezÏ byla dostupna sÏõÂrÏka comfort zone pro prÏedpoklad zachovaÂnõ danger zone 1,5 mm vysveÏtluje z 81% zjisÏteÏne narusÏenõÂm danger zone 1,5 mm v linii B meziaÂlneÏmezirÏezaÂkem a implantaÂtem, resp. ze75% v linii B distaÂlneÏod im-plantaÂtu. ZbylyÂch teÂmeÏrÏ 20 %, resp. 25% variability je trÏeba prÏicÏõÂtat puÊsobenõ jinyÂch faktoruÊ (obr. 8 a obr. 9). PrÏekrocÏenõ prÏipravene dostupne meziodistaÂlnõ sÏõÂrÏky comfort zone v linii B (tj. na spojnici cementosklovin-nyÂch hranic hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku) prÏihy-poteticky plaÂnovane sÏõÂrÏce danger zone 1,5 mm indi-kacõÂsÏi rsÏõÂho pruÊrÏezu implantaÂtu nezÏ byla dostupna sÏõÂrÏka comfort zone nastalo ve 38 prÏõÂpadech, a to pruÊmeÏrneÏ o 0,30±0,25 mm s minimem 0,01 mm a maximem 1,00 mm. O võÂce nezÏ 0,50 mm byla sÏõÂrÏka prÏekrocÏena v 8 prÏõÂpadech.

Ke zjisÏteÏnõÂsõÂly asociace mezi horizontaÂlnõÂm projekcÏ-nõÂm zveÏtsÏeprojekcÏ-nõÂm v oblastihornõÂch rÏezaÂkuÊ na ortopanto-mogramech zhotovenyÂch v cÏase T1, tj. prÏed zavede-nõÂm implantaÂtu, a indikovanou sÏõÂrÏkou pruÊrÏezu implan-taÂtu, ktera zohlednÏuje danger zone, byla korelovaÂna pomocõ Pearsonova koeficientu lineaÂrnõ korelace a koeficientu determinace mõÂra horizontaÂlnõÂho pro-jekcÏnõÂho zveÏtsÏenõÂm v [%] s rozdõÂlem mezidostupnou comfort zone vlinii B a sÏõÂrÏkou pruÊrÏezu zvoleneÂho i m-plantaÂtu v [mm].

PearsonovyÂm koeficientem lineaÂrnõ korelace r ke zjisÏteÏnõ sõÂly asociace mezi horizontaÂlnõÂm projekcÏnõÂm zveÏtsÏenõÂm v [%] v oblastihornõÂch rÏezaÂkuÊ na ortopanto-mogramech zhotovenyÂch v cÏase T1, tj. prÏed zavede-nõÂm implantaÂtu, a rozdõÂlem mezidostupnou comfort zone v linii B a sÏõÂrÏkou pruÊrÏezu zvoleneÂho implantaÂtu v [mm] byla zjisÏteÏna podstatna a statisticky vysoce vyÂ-znamna korelace horizontaÂlnõÂho projekcÏnõÂho zveÏtsÏenõ oblastirÏezaÂkuÊ na ortopantomogramu a a rozdõÂlem mezidostupnou comfort zone a sÏõÂrÏkou pruÊrÏezu zvole-neÂho implantaÂtu (r = -0,56; p<0,001). Viz obr.10.

Koeficient determinacer2 vyjadrÏujõÂcõÂ pomeÏr

vysveÏ-tlene variability k celkove variabiliteÏ indikuje, zÏe mõÂra ho-rizontaÂlnõÂho projekcÏnõÂho zveÏtsÏenõ oblastirÏezaÂkuÊ na ortopantomogramu vysveÏtluje pouze ze 31% meziodi-staÂlnõÂrozdõÂly v sÏõÂrÏce mezidostupnou comfort zone a pruÊ-rÏezem zvoleneÂho implantaÂtu. ZbylyÂch teÂmeÏrÏ 70 % va-riability je trÏeba prÏicÏõÂtat puÊsobenõ jinyÂch faktoruÊ.

Diskuse

Radiograficke vysÏetrÏenõ je v implantologii zaÂkladnõÂm vysÏetrÏenõÂm prÏed implantacõ ke stanovenõ kvantity i kva-lity alveolaÂrnõ kosti. StandardnõÂm implantologickyÂm diagnostickyÂm radiodiagnostickyÂm vysÏetrÏenõÂm ke zji-sÏteÏnõ stavu kostiprÏed implantacõ jsou analogove nebo digitaÂlnõ ortopantomogramy. Jejich vyÂhodou je

jedno-2,0 1,5 1,0 0,5 0,0 −0,5 −1,0 1,05 1,10 1,15 1,20 1,25 1,30 1,35 1,40 x_T1 [%] Def_CZ [mm]

Obr. 10.Asociace mezi narusÏenõÂm comfort zone v [mm] indikova-nyÂm implantaÂtem (Def_CZ) a projekcÏnõÂm horizontaÂlnõÂm zvetsÏenõÂm (x_T1) v [%]. ZaÂporna hodnota znacÏõ deficit.

Fig. 10.Association between disruption of comfort zone in [mm] with the indicated implant (Def_CZ) and projection horizontal magnifica-tion (x_T1) in [%]. Negative value means deficiency.

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gital orthopantomograms represent standard diagno-stic method. Advantages include simple performabi-lity, good availabiperformabi-lity, low costs, low patient radiation dose, and the fact that in one shot there are depicted several anatomical structures. The main disadvantage is - apart from superimposition of tissues - uneven dis-proportional magnification and distortion of anatomi-cal structures. Distortion is further increased due to errors in making OPG, especially by wrong positioning of a patient's head. However, even correctly made OPG with standardized position of head shows magni-fication in the area of upper incisors 125% on the ave-rage. Actual magnification in the area of upper molars is unpredictable and oscillates between 120 and 132% in analogue devices, and between 119 and 131% in case of digital ones [6]. Magnification coefficient may be determined according to radiogram calibration, usually by placing the radio-contrastive body (metal ball the dimensions of which are known) to the site of the planned replacement with the help of a surgical template [5, 7]. By comparison of the actual dimen-sions of an object and the dimendimen-sions of its radiogram we can calculate the magnification coefficient. Howe-ver, in practice the calibration is done at the beginning and only in several cases, and the average value is then calculated. With regard to the interval of potential va-lues of magnification, the average value thus establis-hed may result in incorrect appraisal of the actual width of the space prepared for the implant.

In our sample the average value of projection mag-nification of OPG was 125±7%, minimum = 105%, maximum = 138%. The magnification of OPGs taken prior and after the implantation was comparable. While the mean value of magnification corresponded to va-lues cited in literature [6], dispersion of vava-lues measu-red was greater. This fact is probably due to non-stan-dardized positioning of the head. The projection mag-nification resulted in the difference of width between magnified (measured in OPG) and actual width of the space. This difference was - on the connecting line between the middle of central incisor crown and ca-nine crown 1.53±0.44 mm; on the connecting line of the CEJs of the above given teeth 1.66±0.48 mm; and on the connecting line of apexes of teeth next to the gap 2.22±0.66 mm.

The mean value of mesiodistal width of the space for the replacement of maxillary lateral incisor on the connecting line between maxillary central incisor CEJ and canine CEJ was 6.93±0.62 mm. This corresponds to recommended values cited in literature [2, 10, 15].

Though we had expected the relationship between disruption of danger zone and the extent of OPG di-stortion, this was not proved. However, we found out statistically significant correlation with the diameter ducha proveditelnost, dobra dostupnost, nõÂzka cena

vysÏetrÏenõÂ, nõÂzka radiacÏnõ zaÂteÏzÏ pro pacienta a to, zÏe zo-brazujõ na jednom snõÂmku võÂce anatomickyÂch struktur duÊlezÏityÂch pro implantologa. Jejich hlavnõ nevyÂhodou je kromeÏ superimpozice tkaÂnõ nerovnomeÏrne dispro-porcÏnõ zveÏtsÏenõ a zkreslenõ zaÂjmovyÂch anatomickyÂch struktur. Zkreslenõ se pak daÂle vyÂrazneÏ zvysÏuje vlivem chyb prÏiporÏizovaÂnõ ortopantomogramu, zejmeÂna vad-nyÂm polohovaÂnõÂm hlavy vysÏetrÏovaneÂho pacienta. OvsÏem i rÏaÂdneÏ zhotoveny ortopantomogram se stan-dardizovanou polohou hlavy ma zveÏtsÏenõ v oblastihor-nõÂch rÏezaÂkuÊ pruÊmeÏrneÏ 125 %. ReaÂlne zveÏtsÏenõ pak ne-predikovatelneÏ kolõÂsa v rozmezõÂ120-132 % u konvencÏ-nõÂch prÏõÂstrojuÊ a 119-131 % u digitaÂlkonvencÏ-nõÂch v oblasti hornõÂch molaÂruÊ [6]. Koeficient zveÏtsÏenõ lze zjistit kali-bracirentgenogramu, obvykle umõÂsteÏnõÂm rentgenkon-trastnõÂho teÏlesa (kovove kulicÏky o znaÂmyÂch rozmeÏrech) do plaÂnovaneÂho mõÂsta implantace pomocõ chirurgicke sÏablony [5, 7]. PorovnaÂnõÂm skutecÏne velikosti prÏedmeÏtu a velikosti jeho rentgenoveÂho obrazu lze pak vypocÏõÂtat koeficient zveÏtsÏenõÂ. V praxije ale tato kalibrace nejcÏa-steÏjipro zjednodusÏenõ a urychlenõ praÂce provaÂdeÏna pouze zpocÏaÂtku na neÏkolika prÏõÂpadech a je vypocÏõÂtaÂna pruÊmeÏrna hodnota zveÏtsÏenõ rentgenogramu slouzÏõÂcõ pro dalsÏõ hodnocenõÂ. Vzhledem k rozsahu intervalu mozÏnyÂch hodnot zveÏtsÏenõ ale takto zjisÏteÏna pruÊmeÏrna hodnota zveÏtsÏenõ muÊzÏe veÂst k chybneÂmu posouzenõ skutecÏne sÏõÂrÏky mezery prÏipravene pro implantaÂt.

PruÊmeÏrna hodnota projekcÏnõÂho zveÏtsÏenõ ortopanto-mogramu byla u vysÏetrÏovaneÂho souboru 125±7% s minimem 105% a maximem 138%. Srovnatelne pro-jekcÏnõ zveÏtsÏenõ bylo u ortopantomogramuÊ zhotove-nyÂch prÏed implantacõ i po implantaci. ZatõÂmco pruÊ-meÏrna hodnota zveÏtsÏenõ odpovõÂdala literaÂrnõÂm uÂdajuÊm [6], rozptyl dosazÏenyÂch hodnot byl veÏtsÏõÂ, nezÏ je udaÂvaÂn v literaturÏe. Tato skutecÏnost je velmipravdeÏpodobneÏ daÂna vlivem nestandardizovaneÂho polohovaÂnõ hlavy prÏizhotovovaÂnõ ortopantomogramu. Vlivem projekcÏ-nõÂho zveÏtsÏenõ dosÏlo k rozdõÂlu v sÏõÂrÏce meziprojekcÏneÏ zveÏtsÏenou (meÏrÏenou na ortopantomogramu) a skutecÏ-nou sÏõÂrÏkou mezery. Tento rozdõÂl byl na spojnici strÏedu korunek strÏednõÂho rÏezaÂku a sÏpi cÏaÂku pruÊmeÏrneÏ 1,53±0,44 mm, na spojnici cementosklovinnyÂch hra-nic teÏchto zubuÊ pruÊmeÏrneÏ 1,66±0,48 mm a v mõÂsteÏ spojnice apexuÊ zubuÊ bezprostrÏedneÏ sousedõÂch s me-zerou 2,22±0,66 mm.

PruÊmeÏrna meziodistaÂlnõ sÏõÂrÏka mezery prÏipravene pro implantaci hornõÂho postrannõÂho rÏezaÂku byla na spojnici cementosklovinnyÂch hranic hornõÂho strÏednõÂho rÏezaÂku a sÏpi cÏaÂku pruÊmeÏrneÏ 6,93±0,62 mm. Tato pruÊ-meÏrna sÏõÂrÏka je v souladu s literaÂrneÏ doporucÏenyÂmihod-notami[2, 10, 15].

PrÏisledovaÂnõÂ podõÂlu jednotlivyÂch faktoruÊ na narusÏenõÂ danger zone prÏiimplantacinebyla prokaÂzaÂna naÂmi

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ocÏe-of an implant larger than the available width ocÏe-of comfort zone, both medially between incisor and the implant, and distally between the implant and canine. Never-theless, we failed to determine the factors that would explain indication of the implant with the diameter lar-ger than the available width of comfort zone. The only factor we observed was magnification in OPG. The extent of horizontal projection magnification in the area of incisors (in OPG) explains only 31% of mesio-distal differences in width between the comfort zone available and the diameter of the selected implant. 70% of variability is due to other factors that can be de-termined only hypothetically.

Discussion over the results of our study with implant surgeons who performed surgery revealed that size and shape of crowns represented the indication di-lemma. As we have already stated, today an implant is considered a crown prolongation, and with this view and the view of esthetics it should be used. In case of incisors that are too narrow in mesiodistal dimension and in which the complex esthetic restoration with ve-neers is not planned, the crown of the lateral incisor re-placement would be too massive, or it would be neces-sary to leave spaces next to the crown. In such cases prosthetic indication for narrow (i.e. adequate) crown may be preferred to implantology-periodontical indi-cation for wide ¹danger zoneª.

Conclusion

In our sample the mean mesiodistal width of the space for an implant on the connecting line of CEJs of incisor and canine was 6.93±0.62 mm, which was in agreement with the recommended values. Roots of adjacent teeth ran parallel in 100% of our cases. The study aimed to give the characteristics of spaces orthodontically prepared for the replacement of mis-sing upper lateral incisors from the viewpoint of their suitability for replacement and the relationship of the implant with adjacent teeth. We focused on the so-cal-led comfort zone and danger zone of the implantation in mesiodistal dimension. We also wanted to deter-mine the extent of magnification of diagnostic OPG, and establish whether the magnification had an impact on the judgment of an implant surgeon in the planning of surgical management.

In our sample the average extent of projected mag-nification of OPG was 125±7%, minimum = 105%, maximum = 138%. The magnification was comparable in OPGs made before and after the replacement.

The hypothesis of relationship between the disrup-tion of danger zone and the extent of OPG distordisrup-tion was not proved in our sample. However, we determi-ned statistically significant correlation of the disruption of danger zone and the indication for an implant with kaÂvana souvislost narusÏenõ danger zone s mõÂrou

zkre-slenõ ortopantomogramu. Byla vsÏak zjisÏteÏna statisticky vyÂznamna korelace s indikacõ sÏi rsÏõÂho pruÊmeÏru implan-taÂtu nezÏ byla dostupna sÏõÂrÏka comfort zone, a to jak mezi-aÂlneÏ mezirÏezaÂkem a implantaÂtem, tak distmezi-aÂlneÏ meziim-plantaÂtem a sÏpi cÏaÂkem. Ve studii se nepodarÏilo odhalit faktory, ktere by vysveÏtlovaly indikaci sÏi rsÏõÂho pruÊmeÏru implantaÂtu nezÏ byla dostupna sÏõÂrÏka comfort zone. Jedi-nyÂm naÂmizkoumaJedi-nyÂm faktorem bylo zveÏtsÏenõ na orto-pantomogramu. MõÂra horizontaÂlnõÂho projekcÏnõÂho zveÏt-sÏenõ v oblastirÏezaÂkuÊ na ortopantomogramu vsÏak vysveÏ-tluje pouze v 31 % meziodistaÂlnõ rozdõÂly v sÏõÂrÏce mezi dostupnou ¹comfort zoneª a pruÊmeÏrem zvoleneÂho im-plantaÂtu. ZbylyÂch teÂmeÏrÏ 70 % variability je nutne prÏicÏõÂtat puÊsobenõ jinyÂch faktoruÊ a na ty lze usuzovat jen hypote-ticky. Z konzultace vyÂsledkuÊ studie s implantology, kterÏõ provaÂdeÏli chirurgickou faÂzi, se jako indikacÏnõ dilema jevõ velikost a tvar korunek sousednõÂch rÏezaÂkuÊ. Jak je jizÏ uve-deno vyÂsÏe, implantaÂt je v dnesÏnõÂm pojetõ povazÏovaÂn za prodlouzÏenõ korunky a s teÏmito ohledy na estetiku vyÂ-sledne proteticke praÂce by meÏl byÂt zaveden. Pokud se jedna o meziodistaÂlneÏ uÂzke rÏezaÂky, u kteryÂch nenõÂplaÂno-vaÂna komplexnõ esteticka rekonstrukce fazetami, byla by korunka implantaÂtu postrannõÂho rÏezaÂku prÏõÂlisÏ ro-bustnõÂnebo by bylo nutne ponechat mezery po stranaÂch korunky. V teÏchto prÏõÂpadech pak prÏiplaÂnovaÂnõ muÊzÏe prÏevaÂzÏit proteticka indikace uÂzke (tj. adekvaÂtneÏ velkeÂ) korunky prÏed implantologicko-parodontologickou indi-kacõ sÏiroke ¹danger zoneª.

ZaÂveÏr

V nasÏem souboru byla pruÊmeÏrna meziodistaÂlnõ sÏõÂrÏka prÏipravene mezery na spojnici cementosklovinnyÂch hranic rÏezaÂku a sÏpi cÏaÂku 6,93±0,62 mm, cozÏ koreluje s literaÂrneÏ doporucÏenyÂmihodnotami. KorÏeny zubuÊ sousedõÂch s prÏipravenou mezerou byly ve 100% prÏõÂ-paduÊ paralelnõÂ. CõÂlem studie bylo zjistit charakteristiku mezer ortodonticky prÏipravovanyÂch k zavedenõ im-plantaÂtu na mõÂsto postrannõÂho hornõÂho rÏezaÂku z hledi-ska jejich vyuzÏitelnosti pro zavedenõ implantaÂtu a vztahu implantaÂtu k sousednõÂm zubuÊm se zameÏrÏenõÂm na tzv. bezpecÏnou zoÂnu a nebezpecÏnou zoÂnu implan-tace v meziodistaÂlnõ dimenzi. DõÂlcÏõÂm uÂkolem bylo zjistit mõÂru zveÏtsÏenõ diagnostickeÂho ortopantomogramu, a zda toto zveÏtsÏenõÂmohlo ovlivnit uÂsudek implantologa prÏiplaÂnovaÂnõ implantace.

PruÊmeÏrna hodnota projekcÏnõÂho zveÏtsÏenõ ortopanto-mogramu byla u sledovaneÂho souboru 125±7% s mi-nimem 105% a maximem 138%. ProjekcÏnõ zveÏtsÏenõ bylo srovnatelne u ortopantomogramuÊ zhotovenyÂch prÏed i po implantaci.

V nasÏe souboru se nepotvrdila hypoteÂza zaÂvislosti narusÏenõ danger zone na mõÂrÏe zkreslenõ ortopantomo-gramu. Byla vsÏak zjisÏteÏna statisticky vyÂznamna kore-lace narusÏenõ danger zone s indikacõ sÏi rsÏõÂho pruÊmeÏru

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the diameter larger than the available width of comfort zone, both mesially between incisor and the implant, and distally between the implant and canine. Never-theless, in our sample we did not find the factors that would explain the indication for the implant with dia-meter larger than the available width of comfort zone.

Authors have no commercial, proprietary or financial interest in products or companies mentioned in the article.

implantaÂtu nezÏ byla dostupna sÏõÂrÏka comfort zone, a to jak meziaÂlneÏ mezirÏezaÂkem a implantaÂtem, tak distaÂlneÏ meziimplantaÂtem a sÏpi cÏaÂkem. V naÂmivysÏetrÏovaneÂm souboru vsÏak nebyly nalezeny faktory, ktere by indi-kacisÏi rsÏõÂho pruÊmeÏru implantaÂtu nezÏ byla dostupna sÏõÂrÏka comfort zone vysveÏtlovaly.

AutorÏi nemajõ komercÏnõÂ, vlastnicke nebo financÏnõ zaÂjmy na pro-duktech nebo spolecÏnostech popsanyÂch v tomto cÏlaÂnku.

Literatura/ References

1. Garber, D. A.: The esthetic dental implant: letting restora-tion be the guide. J. Amer. dent. Assoc. 1995, 126, cÏ. 3, s. 319-25.

2. Al-Sabbagh, M.: Implant in Esthetic Zone. Dent. Clin. North Amer., 2006, 50, cÏ. 3, s. 391-407.

3. Belser, U. C., Martin, W. C., Jung, R., Hammerle, C., Schmid, B., Buser, D.: ITI Treatment Guide, Vol I: Implant Therapy in the Esthetic Zone - Single-Tooth Replace-ments. Berlin: Quintessence, 2006.

4. Buser, D., Martin, W., Belser, U. C.: Optimizing esthetics for implant restorations in the anterior maxilla: anatomic and surgical consideration. Int. J. oral maxillofac. Im-plants. 2004, 19, Suppl., s. 43-61.

5. SÏimuÊnek, A. a kol.: DentaÂlnõÂ implantologie. 2nd ed. Hradec KraÂloveÂ: Nucleus, 2008.

6. Park, J. B.: The evaluation of digital panoramic radio-graphs taken for implant dentistry in the daily practice. Med. oral Patol. oral Cir. bucal, 2010, 15, cÏ. 4, s. 663-666. 7. Koeck, B., Wagner, W.: Praxis der Zahnheilkunde 13,

Im-plantologie. MuÈnchen: Urban & Schwarzenberg, 1996.

MUDr. Alena Mottlova Stomatologicka klinika FN

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